<template>
  <div class="spec-preview">
    <img :src="abc" />
    
    <div class="event" v-on:mousemove="handler"></div>
    
    <div class="big">
      <img :src="abc" ref="big" />
    </div>

    <!-- 遮罩层 -->
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script>
export default {
  name: "Zoom",
  props: ["skuInfo"],  
  data() {
    return {
      t: 0,
    }
  },
  computed: {
    abc() { 
      if(this.skuInfo) {     
        if(this.skuInfo.skuImageList.length !== 0) {      
          this.skuInfo.skuDefaultImg = this.skuInfo.skuImageList[this.t].imgUrl;        
          return this.skuInfo.skuDefaultImg;
        }else {                    
          return this.skuInfo.skuDefaultImg;
        }
      }else {    
        return "";
      }     
    }
  },
  methods: {
    handler(event) {
      let mask = this.$refs.mask;
      let big = this.$refs.big;

      let left = event.offsetX - mask.offsetWidth / 2;
      let top = event.offsetY - mask.offsetHeight / 2;
      
      if(left <= 0) {left = 0;};
      if(left >= mask.offsetWidth) {left = mask.offsetWidth};
      if(top <= 0) {top = 0;};
      if(top >= mask.offsetHeight) {top = mask.offsetHeight};

      mask.style.top = top+"px";
      mask.style.left = left+"px";

      big.style.top = -(top*2)+"px";
      big.style.left = -(left*2)+"px";
    }
  },
  mounted() {
    this.$bus.$on("getIndex", (value) => {
      this.t = value;
    })
  },
}
</script>

<style scoped>
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;
  }
  .spec-preview img {
    width: 100%;
    height: 100%;
  }

  .spec-preview .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .spec-preview .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .spec-preview .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;
  }

  .spec-preview .big img {
    width: 200%;
    max-width: 200%;
    height: 200%;
    position: absolute;
    left: 0;
    top: 0;
  }

  .spec-preview .event:hover ~ .mask {
    display: block;
  }
  .spec-preview .event:hover ~ .big {
    display: block;
  }
</style>